Mixing devices are in wide use in industry, and many mixing devices typically include a vessel, which contains a liquid or other material to be mixed, and an impeller shaft running through some or all of a length inside the vessel. The impeller shaft is typically rotatibly driven by a motor, often located at the top of the vessel. There are radially extending impellers, which are mounted to the shaft at one or several axial locations on the length of the shaft and are in the form of paddles or blade type features that extend radially outward from the shaft. The impellers mix and or otherwise impart energy to the material inside of the vessel when the shaft is rotated.
Mixing devices of this type are in wide use, for example in the pharmaceutical, biotechnology, and sanitary food and beverage industries. These industries sometimes present several requirements, which it would be desirable to have met. For example, it is often desirable to be able to change or switch out the shape or size of the impeller being used to permit use of an impeller that will accomplish the desired goals with the material that is to be mixed. For this reason, it would be desirable to have an impeller hub that can be removably mounted on to the shaft, thereby permitting interchanging of different hub impeller arrangements on to a single standard shaft.
Another requirement often found in these industries is easy cleanability and maintenance of sanitary conditions before, during and after mixing. Some known disassemblable hub mounting arrangements can present the problem that during operation the material comes in contact with complex surfaces which are then difficult to clean. For example, known hubs may have exposed screws or numerous gaps that can collect dirt or material. Accordingly, it would be desirable to have a removable impeller hub system that maintains sanitary conditions during operation and easy cleanability before or after use.
Another desirable characteristic in mixers, in addition to being able to interchange different impeller shapes and sizes, is the ability to change the axial location of the impeller hub. Therefore, it would also be desirable to have a removable impeller assembly that provides for axial adjustment if desired.
It would further be desirable to have such an impeller and hub assembly that is economical, requires a relatively few number of parts, and that can be simple to install and uninstall.